Ophiolites: -pieces of oceanic crust thrusted (obducted) onto the edge of continental plates; - assemblage of mafic (basalt) and ultramafic (perodotite) lavas found in association with sedimentary rocks; -found in Cyprus, New Guinea, Newfoundland, California, Turkey, and Oman. Semail ophiolite in southeastern Oman probably formed in the Cretaceous not far from what is now the Persian Gulf. The rocks were later thrust (pushed uphill at a low angle) westward onto the Arabian shield.
SUBDUCTION ZONES …and now for something completely different:
“destructive” and “converging” plate boundaries
Two types of destructive plate boundaries: - oceanic crust subducted under oceanic crust - oceanic crust subducted under continental crust [oceanic (basaltic) crust is denser than continental (granitic) crust]